Surya Electro Control offers Low Tension - L.T. Automatic Voltage Regulator. Surya Electro Control manufactures LT and HT Servo Voltage Stabilizers, Silicon Rectifiers, Control and Panels Distribution Transformers and Transformers with built -in HT - Automatic Voltage Regulator. The L.T. Automatic Voltage Regulator are essentially auto wound transformers having Single Layer helical - coil mounted on a conventional laminated transformer core. The L.T. Automatic Voltage Regulator consists of self lubricated graphite rollers, assembled on backelite carrier boards that traverse the length of the coil track.